1. Field of the Invention
The present invention relates generally to electronic chassis and cabinets.
2. Description of the Prior Art
Modular chassis of the prior art generally include a frame with an open front and a plurality of connectors for printed circuit cards positioned at the rear. Use of a chassis involves interconnecting such connectors with interconnection buses. The cards are then inserted into the front of the frame until they are mated with the connectors. The chassis is then usually enclosed by a cabinet. Additional electrical components, such as relays, may be attached directly to the frame or the cabinet and interconnected with the bus or the connectors.
Such chassis have enclosures of two general types. In one type, the enclosure fully encloses the chassis on all sides except the front. The enclosure and chassis combination may be portable or may be mounted on a wall or table. Generally, the back panel of the enclosure is removable to permit access to the connectors for interconnecting buses, installing electronic components, and making modifications or repairs. Several problems are encountered in using such chassis. The electronic components may interfere with making repairs or modifications on the connectors. Also, the buses themselves may interfere with making repairs or modifications on the electronic components. Additionally, if the unit is mounted such that the back panel is against the wall, the entire combination must be removed in order to make modifications or repairs.
The other type of enclosure includes racks on which a plurality of chassis can be mounted. Repairs and modifications can be made in any of several ways. If the chassis are drawer mounted, they may be pulled outwardly from the rack thus exposing the connectors, buses and electrical components. If the chassis is not drawer mounted, it can be removed from the rack and placed on a work surface. If the enclosures have rear access, such as a rear door or removable panel, repairs or modifications can be made through such access. None of these techniques, however, is satisfactory. Drawer mounting of the chassis is costly and results in wasted space. Also, carrying the chassis to a remote work area may result in damage. Additionally, the chassis may be too heavy to be easily carried. Moreover, a substantial amount of extra space is needed and additional expense is incurred if the enclosure has rear access.
Furthermore, the width of a rack mountable chassis is governed by the width of the rack. Therefore, the number of units that can be accommodated by a chassis is limited. Furthermore, wasted space results if the units do not take up the entire width of the chassis.